The prior art is already aware of various apparatus for adjusting the clearance between the reel and a bedknife in a lawn mower. In some instances, the bedknife is the movable member, and, in other instances, the reel is the movable member. For instance, in U.S. Pat. No. 3,187,492, the bedknife is movable through a threaded adjustment for establishing the position of the bedknife relative to the reel. Also, U.S. Pat. No. 3,106,813 shows the adjustment of the bedknife relative to the reel. U.S. Pat. No. 3,685,265 and U.S. Pat. No. 4,345,419 show movement of the reel relative to the bedknife. Further, U.S. Pat. No. 4,516,388 shows the application of hydraulics for moving the bedknife relative to the reel to establish the clearance therebetween. Also, U.S. Pat. No. 2,789,712 shows hydraulic apparatus for positioning a tractor shovel. U. S. Pat. No. 4,335,569 uses monitoring means.
The present invention differs from the prior art in that it provides for an adjustment of one of the two elements in the reel and bedknife arrangement, whereby the adjustment is accurate and readily accomplished and can be made according to a desired or selected clearance. In the specific embodiment disclosed herein, the adjustment is accomplished through the use of a fluid acuated assembly, which may be either pneumatic or hydraulic.
In achieving the adjustment through the use of this invention, one can select the desired clearance, in the field, and the two cutting elements are then brought into contact. The desired clearance is then established, as selected, and further actuation of the apparatus will then automatically move the cutting elements into their clearance position, as desired. That is, the present invention provides for a ready and easy selection for the desired amount of clearance between the cutting elements, and thus the accurate and desired clearance can be selected and established, in the field. Further, the present invention provides that the cutting elements can be readily released from their set position relative to each other, for purposes of sharpening the cutting elements or for any other purpose.
The present invention provides for minute dimensional adjustments, such as 0.001 to 0.003 inches, to provide for the optimum adjustment of the cutting elements and to avoid excessive wear between the respective cutting edges and yet assure that the grass will be well mowed.
Still further, the present invention provides for apparatus whereby one can set the clearance between the cutting elements and do so in a manner independent of utilizing a specific displacement of a certain quantity of hydraulic fluid.